1. Field of the Invention
The present invention relates to navigation systems for data collections.
2. Description of Related Art
As memory devices are able to store greater amounts of data in smaller spaces, it is becoming increasingly difficult for users to effectively navigate through stored data in order to find items of interest. For example, today's MP3 players are capable of storing thousands of songs, and presumably this number will only increase through the years. While having thousands of stored songs to select from offers the user a wide range of variety, it also increases the complexity and frustration that might be felt by the user when trying to find a particular song to listen to. Moreover, unless the user has a clear choice in mind, sometimes the sheer number of choices available makes it almost impossible for a user to decide what to listen to. Furthermore, because MP3 players are typically portable, there is significant pressure to produce smaller and smaller players, which results in smaller and smaller display screens, which can make item selection even more difficult, as a user may have to navigate through many different screens in order to find a desired item.
Moreover, in some cases, a user may be provided with a collection of items the contents of which are entirely unknown to the user. These types of “blind” data navigation situations are often encountered, for example, on the internet. For instance, a museum may provide a website catalogue including pictures of some or all of their pieces. A user may wish to navigate through the museum catalogue, either to find a particular item or interest, or simply to browse the collection. However, even a small museum may have thousands upon thousands of individual items in their collection and finding a particular item or browsing through so many items in such a large collection can be a daunting task.
Accordingly, systems for large-scale data navigation have been proposed. Typically, these systems rely on information that has been associated with each data item, generally referred to as “metadata,” in order to categorize a given data item. The metadata often consists of a number of orthogonal attributes, which may or may not be arranged in a hierarchy or taxonomy. For example, a given MP3 song may include metadata providing the song's title, artist, album title, distributor, genre, etc.
Some data navigation tools use a strict hierarchy of metadata attributes. For example, a music browsing scheme may require that the user first select an artist, then an album title, and then a song. However, such a hierarchical approach may not work in all situations, for example when a user does not know the name of the artist performing a particular or song, or when a given song's metadata does not include the artist's name.
Faceted metadata systems do not use a hierarchical system and instead considers all the different attributes to be equal facets of the items. Faceted systems typically allow users to view all the different facets, or metadata categories, available for the items in the collection and then progressively pick, in any sequence, facets that narrow the collection. Examples of faceted metadata systems include UC Berkeley's Flamenco system and HPL Bristol's SWAD-E system. See also, Ranganathan, S. R. Elements of Library Classification. 3rd ed. New York, Asia Publishing House (1962). However, while these faceted systems allow users to select items based on all available metadata, they generally do very little to guide the user as to which facet, among possibly hundreds, will be most useful in navigating a collection. Moreover, many of these systems use a static pre-assigned list of metadata categories so that items are only categorized properly if they include metadata that satisfies one of the pre-assigned metadata categories. Furthermore, when dealing with systems where user displays or interfaces have a limited size, a system that provides a user with a large number of selections from which to choose is cumbersome and often impractical. Accordingly, it will be appreciated that alternate methods and systems for data navigation are desirable.